I tried the community edition and liked it so much I bought 2.2.2 but it is a 32 bit app so will not run. That leaves a few options and I would like advice on the pros and cons.

Install Alien Bob's multilib so the 32 bit QCad will run. I am reluctant to go through this non-trivial exercise because I don't need to run any other 32 bit apps.

Get the 2.2.2 source (how?) and compile 2.2.2 as a 64 bit app. A road seldom (ever?) travelled so likely troublesome. Both QT3 and QT4 are installed so the build could be with either. Most of the online pages about building QCad are about building with QT4; they don't inspire much confidence of success but at least there is some info available.

Download QCad 3TP and hope for the best. Is it a 64 bit package anyway? I'm a new naive user with simple drawing intentions so a TP might be good enough.

Switch to LibreCAD (am I allowed to mention that here?). The build instructions are only for Ubuntu and Debian so that would be another lonely untravelled road.

We've had some disappointing results with QCAD 3 64bit (see http://www.ribbonsoft.com/qcad3.html), so if you plan on using QCAD and don't absolutely need 64bit, I'd recommend to go with a 32bit Linux distribution.

Projects like Librecad (QCAD forks) pop up every now and then and usually disappear again once the person behind it has no longer the time to keep it up.